Hydrocarbon resource processing device including radio frequency applicator and related methods

ABSTRACT

A hydrocarbon resource processing device may include a radio frequency (RF) source and an RF applicator coupled to the RF source. The RF applicator may include a base member being electrically conductive, and first and second elongate members being electrically conductive and having proximal ends coupled to the base member and extending outwardly therefrom in a generally parallel spaced apart relation. The first and second elongate members may have distal ends configured to receive the hydrocarbon resource therebetween. In another embodiment, the RF applicator may include an enclosure being electrically conductive and having a passageway therethrough to accommodate a flow of the hydrocarbon resource and a divider being electrically conductive and positioned within the enclosure.

FIELD OF THE INVENTION

The present invention relates to the field of hydrocarbon resourceprocessing, and, more particularly, to hydrocarbon resource processingdevices including radio frequency applicators and related methods.

BACKGROUND OF THE INVENTION

A hydrocarbon resource may be particularly valuable as a fuel, forexample, gasoline. One particular hydrocarbon resource, bitumen, may beused as a basis for making synthetic crude oil (upgrading), which maythen be refined into gasoline. Accordingly, bitumen, for example, may berelatively valuable. More particularly, to produce 350,000 barrels a dayof bitumen based synthetic crude oil would equate to about 1 billiondollars a year in bitumen. Moreover, about 8% of U.S. transportationfuels, e.g., gasoline, diesel fuel, and jet fuel, are synthesized orbased upon synthetic crude oil.

In the hydrocarbon upgrading or cracking process, hydrogen is added tocarbon to make gasoline, so, in the case of bitumen, natural gas isadded to the bitumen. Natural gas provides the hydrogen. Bitumenprovides the carbon. Certain ratios and mixes of carbon and hydrogen aregasoline, about 8 carbons to 18 hydrogens, e.g. CH₃(CH₂)₆CH₃. Gasolineis worth more then either bitumen or natural gas, and thus the reasonfor its synthesis.

One process for cracking the hydrocarbons is fluid catalytic cracking(FCC). In the FCC process, hot bitumen is applied to a catalyst, forexample, AlO₂, at 900° C. with a relatively small amount of water toform synthetic crude oil. However, the FCC process has a limitedefficiency, about 70%. The residual, also known as coke, is worth farless. Moreover, coke residues stop the FCC process, and the there is anincreased risk of fires and explosions. The FCC process also has a poormolecular selectivity, and produces relatively high reactant emissions,especially ammonia. The catalyst used in the FCC process also has arelatively short lifespan.

Several references disclose application of RF to a hydrocarbon resourceto heat the hydrocarbon resource, for example, for cracking. Inparticular, U.S. Patent Application Publication No. 2010/0219107 toParsche, which is assigned to the assignee of the present application,discloses a method of heating a petroleum ore by applying RF energy to amixture of petroleum ore and susceptor particles. U.S. PatentApplication Publication Nos. 2010/0218940, 2010/0219108, 2010/0219184,2010/0223011, 2010/0219182, all to Parsche, and all of which areassigned to the assignee of the present application disclose relatedapparatuses for heating a hydrocarbon resource by RF energy. U.S. PatentApplication Publication No. 2010/0219105 to White et al. discloses adevice for RF heating to reduce use of supplemental water added in therecovery of unconventional oil, for example, bitumen.

Several references disclose applying RF energy at a particular frequencyto crack the hydrocarbon resource. U.S. Pat. No. 7,288,690 to Bellet etal. discloses induction heating at frequencies in the range of 3-30 MHz.More particularly, radio frequency magnetic fields are applied toferrous piping that includes hydrocarbons. The magnetic fields inductionheat the ferrous piping and the hydrocarbons inside are warmedconductively. Application Publication No. 2009/0283257 to Beckerdiscloses treating an oil well at a frequency range of 1-900 MHz and nomore than 1000 Watts, using a dipole antenna, for example.

Further improvements to hydrocarbon resource upgrading may be desirable.For example, it may be desirable to increase the efficiency of thebitumen to gasoline conversion process, i.e. upgrading, by making itquicker and cheaper, for example.

SUMMARY OF THE INVENTION

In view of the foregoing background, it is therefore an object of thepresent invention to increase the efficiency of hydrocarbon resourceupgrading.

This and other objects, features, and advantages in accordance with thepresent invention are provided by an apparatus for processing ahydrocarbon resource including a radio frequency (RF) source, and an RFapplicator coupled to the RF source. The RF applicator includes a basemember that is electrically conductive. The RF applicator also includesfirst and second elongate members that are electrically conductive andhave proximal ends coupled to the base member and extending outwardlytherefrom in a generally parallel spaced apart relation. The first andsecond elongate members have distal ends configured to receive ahydrocarbon resource therebetween. The RF source and the RF applicatorare configured to generate electrical fields between the distal ends ofthe first and second elongate members to perform at least one ofheating, dehydrating, cracking and hydrogenation of the hydrocarbonresource, for example. Accordingly, the hydrocarbon resource processingapparatus may provide increased efficiency in hydrocarbon resourceupgrading.

The apparatus may include an enclosure being electrically conductive andsurrounding the RF applicator, for example. The enclosure may have apassageway therethrough aligned with the distal ends of the first andsecond elongate members to accommodate a flow of the hydrocarbonresource therebetween, for example.

The RF applicator may further include first and second plates beingelectrically conductive and coupled to respective distal ends of thefirst and second elongate members. The first and second plates may bearranged in parallel opposing relation, for example.

The RF applicator may further include at least one tuning member coupledbetween the first and second elongate members. The apparatus may furtherinclude a coaxial feedline coupling the RF source to the first andsecond elongate members, for example. The RF source may be configured tosupply RF power at 27 MHz, for example.

The may further include a hydrocarbon separator downstream from the RFapplicator and being configured to generate hydrocarbon fractions. Theapparatus may further include a hydrocarbon processor downstream fromthe hydrocarbon separator and being configured to generate at least oneliquid fuel from the hydrocarbon fractions. The hydrocarbon resource mayinclude at least one of oil sand, bitumen, pipeline diluted bitumen,crude oil, and synthetic crude oil, for example.

A related method aspect is directed to a method for processing ahydrocarbon resource. The method includes applying radio frequency (RF)power from an RF source to an RF applicator coupled to the RF source.The RF applicator includes a base member that is electricallyconductive, and first and second elongate members that are electricallyconductive and may have proximal ends coupled to the base member andextending outwardly therefrom in a generally parallel spaced apartrelation. The first and second elongate members have distal ends. Themethod further includes flowing the hydrocarbon resource between thedistal ends to process the hydrocarbon resource with the RF power.

Another aspect is directed to another apparatus embodiment forprocessing a hydrocarbon resource. The apparatus includes a radiofrequency (RF) source and an RF applicator coupled to the RF source. TheRF applicator includes an enclosure being electrically conductive andhaving a passageway therethrough to accommodate a flow of a hydrocarbonresource. The RF applicator also includes a divider being electricallyconductive and positioned within the enclosure.

The RF source and the RF applicator may be configured to perform atleast one of heating, dehydrating, cracking and hydrogenation of thehydrocarbon resource, for example. The divider may have an elongateshape with opposing ends coupled to adjacent portions of the enclosureand with opposing sides spaced inwardly from adjacent portions of theenclosure. The divider may have a convex shape, for example.

A related method aspect is directed to a method for processing ahydrocarbon resource. The method includes applying radio frequency (RF)power from an RF source to an RF applicator coupled to the RF source.The RF applicator includes an enclosure being electrically conductiveand having a passageway therethrough to accommodate a flow of thehydrocarbon resource, and a divider being electrically conductive andpositioned within the enclosure. The method further includes flowing thehydrocarbon resource through the passageway to process the hydrocarbonresource with the RF power.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a portion of an apparatus forprocessing a hydrocarbon resource in accordance with the presentinvention.

FIG. 2 is a schematic diagram of the apparatus in FIG. 1 including across-sectional view of the enclosure.

FIG. 3 is a time versus temperature graph of four samples of thehydrocarbon resource treated by the prototype apparatus.

FIG. 4 is a viscosity graph for a hydrocarbon resource before and aftertreatment by the prototype apparatus.

FIG. 5 is a chemical change graph of a hydrocarbon resource treated bythe prototype.

FIG. 6 is a schematic diagram of a portion of an apparatus forprocessing a hydrocarbon resource in accordance with another embodimentof the present invention.

FIG. 7 is a schematic diagram of a portion of an apparatus forprocessing a hydrocarbon resource in accordance with another embodimentof the present invention.

FIG. 8 is an enlarged cross-sectional view including E-fields andH-fields of the portion of the apparatus of FIG. 7 taken along line 8-8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout, and prime and multiplenotation is used to indicate similar elements in alternativeembodiments.

Referring initially to FIGS. 1 and 2, an apparatus 20 for processing ahydrocarbon resource 21 is illustrated. The hydrocarbon resource 21 maybe at least one of oil sand, bitumen, pipeline diluted bitumen, crudeoil, and synthetic crude oil, for example. The hydrocarbon resource 21may be transported by conduit 41, which may include a pipeline, whichmay be round, square, or other shape, and that may have a dielectriccasing, or a gravity feed chute, for example. In other embodiments thehydrocarbon resource 21 may be transported by a conveyor belt or shaketable.

The apparatus 20 includes a radio frequency (RF) source 22 and an RFapplicator 23 coupled to the RF source. The RF source 22 is configuredto supply RF power at 27 MHz, and, more particularly, at 27.12 MHz. Aswill be appreciated by those skilled in the art, 27.12 MHz is anantiresonance frequency of water so that the RF energy propagatesrelatively deeply into the hydrocarbon resource 21. The RF applicator 23may be considered an electrically small structure with most dimensionssmaller than one wavelength λ, for example. A hydrocarbon resource 21that has passed through the RF applicator 23 may be considered treated.The hydrocarbon resource 21 may be batch treated or treated as acontinuous flow or stream.

The RF applicator 23 includes a base member 24 that is electricallyconductive. The RF applicator 23 also includes first and second elongatemembers 25, 26 that are electrically conductive and have proximal ends27, 28 coupled to the base member 24 and extending outwardly therefromin a generally parallel spaced apart relation. The first and secondelongate members 25, 26 have distal ends 31, 32 configured to receivethe hydrocarbon resource therebetween. Thus, the RF applicator 23 may beconsidered an “RF heating fork”. The RF applicator 23 may be a metallicmaterial, for example. Of course, the RF applicator 23 may be anotherelectrically conductive material. The elongate dimension γ of the RFapplicator 23 may preferably be about a quarter wavelength at theoperating frequency so that natural resonance may be obtainedelectrically.

A coaxial feedline 42 illustratively couples the RF source 22 to thefirst and second elongate members 25, 26. The coaxial feedline 42includes an inner conductor 43 and outer conductor 44. A dielectricmaterial layer 45 is between the inner conductor 43 and the outerconductor 44. The inner conductor 43 is illustratively coupled to thesecond elongate member 26 and the outer conductor 44 is coupled to firstconductor 25. The coupling location of the inner conductor 43 to thesecond elongate members 26 may advantageously determine a resistance.

Other connection arrangements between the coaxial feedline 42 and the RFapplicator 23 may also be used, such as, for example. More particularly,jumpers from the inner conductor 43 and outer conductor 44 may beconnected at various locations along the first and second elongatemembers 25, 26 to obtain any desired electrical load resistance from theRF applicator 23. For example, when the inner conductor 43 and outerconductor 44 are connected to the RF applicator 23 at the base member24, a low resistance is obtained, and when the inner conductor 43 andouter conductor 44 are connected near the distal ends 31, 32, a highresistance is obtained. The 50 ohms point is relatively close to oralong the base member 24 when the RF applicator 23 is unloaded byhydrocarbons.

The RF source 22 and the RF applicator 23 are configured to generateelectrical fields between the distal ends 31, 32 of the first and secondelongate members 25, 26. The electrical fields between the distal ends31, 32 advantageously perform at least one of heating, dehydrating,cracking, and hydrogenation of the hydrocarbon resource 21, for example.In other words, the first and second elongate members 25, 26 provide aparallel conductor transmission line, a distributed impedance matchingelement, or distributed linear transformer.

As will be appreciated by those skilled in the art, current and voltagehave a sine and cosine relationship along the first and second elongatemembers 25, 26, and field impedance, the ratio of the near electric tothe near magnetic fields, varies with the tangent function. The RFapplicator 23 generates primarily near fields, although far fieldradiation may also be generated. Additionally, high voltage may bedeveloped between the distal ends 31, 32, and high currents may bedeveloped in the base member 24. Strong electric fields may also beformed between the distal ends 31, 32, and strong magnetic fields may beformed near the base member 24.

Moreover, different chemical effects have been observed at either end ofthe RF applicator 23, and magnetic fields at the base member 24 may beeffective in converting aromatic molecules to polar molecules, andelectric fields between the distal ends 31, 32 have been effective incracking hydrocarbons. In some instances, more than one RF applicator 23may be used to apply both electric and magnetic fields. As will beappreciated by those skilled in the art, heating, dehydrating, cracking,and hydrogenation of the hydrocarbon resource 21 is a relativelyimportant step in upgrading or synthesizing the hydrocarbon resource toproduce, gasoline or other transportation fuels, for example.

The RF applicator 23 also includes first and second plates 35, 36 thatare also electrically conductive and coupled to respective distal ends31, 32 of the first and second elongate members 25, 26. The first andsecond plates 35, 36 are illustratively arranged in parallel opposingrelation. The first and second plates 35, 36 advantageously increase theuniformity of the parallel electrical fields. More particularly, nearlystraight flux line electric fields are provided between the first andsecond plates 35, 36. In other words, without the first and secondplates 35, 36 non-uniform heating or hot-spots may occur.

The RF applicator 23 further includes a tuning member 37 coupled betweenthe first and second elongate members 31, 32. The tuning member 37 isillustratively a capacitor. The tuning member 37 may be another device,component, or circuitry to adjust the frequency of the electric field.Of course, more than one tuning member 37 may be used and/or more thanone type of tuning member may be used. A larger value capacitive tuningmember 37 may be used allow shorter elongate dimension γ and aninductive tuning member 37 may be used to allow a longer elongatedimensions γ.

Setting the RF source 22 to the spot frequency of 27 MHz, or, moreparticularly, 27.12 MHz, has the synergy of reducing residual waterheating. Using the water antiresonance frequency is particularlyadvantageous with bitumen as the hydrocarbon resource, for example, asthe bitumen readily cracks at that frequency, water heating is reducedat that frequency, and penetration depth, or half depth of penetrationof the electric field, is increased at that frequency. The joinedaromatic ring molecules (polycyclics) are separated from one another“cracking” the oil. Of course, the RF applicator 23 may be used atfrequencies away from 27 MHz if increased water heating or dessicationis desired.

Since bitumen ore, for example, may include up to 15 percent water and“dewatered bitumen,” for example, may include 1 to 2% water residue, itmay be of particular interest that RF fields attack the bitumen insteadof the water. Operation on a molecular resonance spot frequency may notbe needed to RF heat a material, as confirmed by testing.

The RF source 22 may be adjusted to control the heating of thehydrocarbon resource 21, for example, to a desired temperature or level.For example, RF power may be reduced when at 100% desiccation to controlthe rise of the temperature and/or manage the loss of evaporativecooling. A controller or other circuitry may be included to adjust theRF source power based upon, for example, temperature, desiccation, andtime.

The apparatus 20 also includes an enclosure 33 that is electricallyconductive and surrounds the RF applicator 23 (FIG. 2). The enclosure 33has a passageway 34 therethrough aligned with the distal ends 31, 32 ofthe first and second elongate members 25, 26 to accommodate a flow ofthe hydrocarbon resource 21 therebetween. The enclosure 33 may beoperable as an electrical field shield, for example. The enclosure 33may be a metallic material, for example. Of course, the enclosure 33 maybe another electrically conductive material.

The apparatus 20 may further include a hydrocarbon separator 46downstream from the RF applicator 23. The hydrocarbon separator 46 maybe configured to generate hydrocarbon fractions as will be appreciatedby those skilled in the art. The hydrocarbon separator 46 may alsoretort the hydrocarbon resource 21. The apparatus 20 may further includea hydrocarbon processor 47 downstream from the hydrocarbon separator 46.The hydrocarbon processor 47 may be configured to generate a liquid fuelfrom the hydrocarbon fractions as will be appreciated by those skilledin the art. The hydrocarbon processor 47 may also be configured tohydrogenate and/or reformate the hydrocarbon resource, for example. Forexample, gasoline may be generated from the hydrocarbon fractions. Ofcourse, other types of liquid fuels may be generated from thehydrocarbon fractions.

As will be appreciated by those skilled in the art, the apparatus 20 mayprovide lower cracking temperature so little to no coking over thermalcracking and fluid catalytic cracking, for example. In contrast, a fluidcatalytic cracker (FCC) as in the prior art has to be shut down and thecoke ground out mechanically.

When insoluble asphaltenes are deposited on an FCC hot heat exchangersurface, they may form coke, depending on the time and temperature.Above 370° C. this reaction is almost instantaneous and below 200° C. ittypically does not happen in many years. The significance is that oncecoke forms, it cannot be redissolved in the oil or any solvent. This isthe reason that the fouling of the highest temperature heat exchanger inthe crude unit is usually the greatest even though asphaltene solubilityis more at higher temperatures. Once asphaltenes are insoluble at lowertemperatures, the time scale of redissolution is much longer than thetime it takes the crude to flow through the crude unit as the crude isheated to higher temperatures.

A prototype apparatus similar to that described above with respect toFIGS. 1 and 2 was used with bottled samples of asphalt and bitumen fortesting purposes. The bitumen sample had about 2% to 3% water. Theasphalt sample was powdered anhydrous asphalt crystals. The asphaltsample did not react chemically in the test.

The bitumen sample was held in an open-top glass bottle. The glassbottle was surrounded by a Teflon frame including a Teflon lid. Anitrogen feed hose was inserted into the Teflon frame adjacent theopening of the glass bottle to provide a nitrogen flood. The nitrogenflood advantageously reduces reactions with atmospheric oxygen, forexample, so that the chance of a fire was reduced. A thermometer wasalso inserted into the Teflon frame adjacent the opening of the glassbottle. The Teflon frame with the glass bottle was placed between thefirst and second plates.

The RF power source was set to the 27.12 MHz antiresonance frequency ofliquid water. The equipment used for the test included a Bird 4421 powermeter, a Palstar AT5K impedance matching unit, an HP 8656B signalgenerator, and a Continental 618 RF power amplifier, which is capable ofproducing up to 2000 Watts at the 27.12 MHz frequency.

Energy maps were simulated for the glass bottle of bitumen. The energysample maps were taken along the X-Y plane cut in a plan view at 6.78MHz, 150 Watts to the first and second elongate members, and at timet=0. The energy maps showed that inside the bitumen there was anelectric field of 1600 v/m, a magnetic field (H-field) of 0.12 A/m,heating at a volume loss density of 14 W/m³, and a referred electriccurrent (induced) in the bitumen of amplitude 0.23 A/m³. Relativelystrong electric fields were predominant within the glass bottle. Inother words, 1600 volts per meter and 0.12 amps per meter is a very highE-field strength relative to H-field strength. In free space and forradio waves, a 1600 volts per meter E-field would be accompanied by a1600/120π=2.24 amps per meter H-field. The E to H field ratio (impedanceZ) was 2.24/0.12=12 times higher than for radio waves. The fieldimpedance in the test was Z=E/H=1600/0.12=13333 ohms.

Referring now to the graph in FIG. 3, a time versus temperature graph isillustrated for four different samples of bitumen 71, 72, 73, 74. Theelectric fields heated the samples.

Several empirical observations were made. First, all of the residualwater boiled off as steam. Second, gasses were liberated, however, somegasses condensed in the top of the bottle as thin liquids, likelynaptha, for example. A vertical viscosity gradient was also observedthrough the bottles; light thin liquid hydrocarbons on top, viscoushydrocarbons in the middle, and thick hydrocarbons on the bottom.

Referring now to the graph in FIG. 4, viscosity results before heating75 and after heating 76 are illustrated. The electric fields made thebitumen sample [(5.5×10⁵−3.5×10⁵)/3.5×10⁵]×100%=57% more viscous thanthe untreated control sample. This is consistent with cracking thehydrocarbon resource and releasing the light volatiles (which were notrecovered in this test). In summary, the viscosity increased because thelight thin liquid hydrocarbons were boiled off, and the electric fieldscracked the hydrocarbon resources. A condenser or fractionating columnmay of course be provided to capture and separate the lights, as will beappreciated by those skilled in the art.

The test data summary for the prototype apparatus is below in Table. 1

TABLE 1 Parameter Value Antenna Parallel conductor fork TransmitterPower 150 Watts nominal Frequency ~27.12 MHz (water antiresonance)Realized E Field 1600 V/m (the predominant applied energy) Realized HField 0.12 A/m Realized Volume 14 W/m³ Loss Density Realized Induced0.23 A/m² Conduction Current Process Time 30 to 360 minutes, dependingon the sample # Of Samples 4 Processed Feedstock Dewatered AthabascaBitumen (samples 1-4). Asphalt (sample 5). Sample Size 113 grams in eachbottle Outcome, Physical Heating, fractionation (thin oils on effectsrose to top of the bottle), volitization Outcome, Molecular Cracking ofpolycyclics Effects Realized Process Electromagnetic hydrocarboncracking

Referring now to the graph in FIG. 5, the American Society for Testingand Materials (ASTM) results for the feed bitumen and the product of athirty minute trial of being exposed to the generated electrical fields.The dehydrated bitumen is illustrated by the line 77, and bitumenexposed to electrical fields is illustrated by line 78. The boilingrange of the bitumen shifted relative to the feed bitumen. The shift isconsistent with cracking with the subsequent loss of light components,and is demonstrated over the entire range of the boiling pointdistribution (ASTM D 7169 analysis). This test had the highest initialheating rate but it only reached a maximum temperature of about 104° C.,and stayed above 100° C. for a few minutes. It was observed that part ofthe sample boiled during test.

A method aspect is directed to a method for processing a hydrocarbonresource 21. The method includes applying radio frequency (RF) powerfrom an RF source 22 to an RF applicator 23 coupled to the RF source.The RF applicator 23 includes a base member 24 that is electricallyconductive, and first and second elongate members 25, 26 that areelectrically conductive and may have proximal ends 27, 28 coupled to thebase member and extending outwardly therefrom in a generally parallelspaced apart relation. The first and second elongate members 25, 26 havedistal ends 31, 32. The method further includes flowing the hydrocarbonresource 21 between the distal ends 31, 32 to process the hydrocarbonresource with the RF power.

Referring now to FIG. 6, an apparatus 20′ for processing a hydrocarbonresource according to another embodiment is illustrated. The coaxialfeedline 42′ includes an inner conductor 43′ and outer conductor 44′.The coaxial feedline 42′ illustratively couples the RF source 22′ to thefirst and second elongate members 25′, 26′ via a toroidal transformer46′. The toroidal transformer 46′ includes a toroidal core 47′ which maybe a ferrite or powdered iron core, for example, and a conductivewinding 48′ around the toroidal core 47′. The inner conductor 43′ andthe outer conductor 44′ each couple to an end of the conductive winding48′. The base member 24′ passes through the toroidal transformer 46′ sothe conductive winding 48′ functions as a transformer primary winding,and the base member functions as a secondary “winding”. The base member24′ is not a multiple turn winding in a traditional transformer sense,but rather a fractional turn winding. This advantageously provides 50ohms, and may provide other electrical load resistances from the RFapplicator 23′ by adjustment of number of turns in conductive winding48′. The toroidal transformer 46′ may also provide a balun to reduce oreliminate common mode currents from the outside of outer conductor 44′,as will be appreciated by those skilled in the art. Additional or otherconnection arrangements, such as those described above with respect toFIG. 1, may be used, for example, to obtain a desired electrical loadresistance.

Referring now to FIGS. 7-8, an apparatus 20″ for processing ahydrocarbon resource according to another embodiment is illustrated. Thehydrocarbon resource 21″ may be transported by conduit 41″. Water may beinjected into the conduit 41″ to serve as a radio frequency heatingsusceptor, for example, and/or to donate hydroxyl radicals (OH—) toinitiate reactions, as will be appreciated by those skilled in the art.

The apparatus 20″ includes a radio frequency (RF) source 22″ and an RFapplicator 23″ coupled to the RF source. The RF source 22″ is configuredto supply RF power at 27 MHz and, more particularly, 27.12 MHz.

The RF source 22″ and RF applicator 23″ are configured to perform atleast one of heating, dehydrating, cracking and hydrogenation of thehydrocarbon resource 21″. The RF applicator 23″ may be considered as anelectrically small structure with most dimensions smaller than onewavelength λ.

The RF applicator 23″ includes an enclosure 33″ that is electricallyconductive and has a passageway 34″ therethrough to accommodate a flowof the hydrocarbon resource 21″. The conduit 41″ enters and exits theenclosure 33″ through the passageway 34″ which may include evanescentapertures or holes or openings in the enclosure that are electricallysmall, e.g. their physical dimensions are small relative the wavelengthof the radio frequency oscillations, for example.

The RF applicator 23″ also includes a divider 51′ that is alsoelectrically conductive and is positioned within the enclosure 33″. Thedivider 51″ has an elongate shape with opposing ends 52″, 53″ coupled toadjacent portions of the enclosure 33″. The divider 51″ also hasopposing sides 54″, 55″ spaced inwardly from adjacent portions of theenclosure 33″. The divider 51″ is narrower than the width of theenclosure 33″.

The divider 51″ illustratively has a convex shape. The divider 51″ maybe planar, or it may have a concave or other shape to reduce fringingfields or to control electromagnetic field amplitude tapers, as will beappreciated by those skilled in the art. The divider 51″ may be anothershape. The divider 51″ may be a metallic material, such as, for example,a metallic sheet, or other electrically conductive material, as will beappreciated by those skilled in the art.

The elongate dimension α of the divider 51″ may be about ½ wavelength atthe desired radio frequency, e.g. α=ck/2f where c is the speed of light,k is the loading effect of the hydrocarbon resource 21″, and f is thedesired radio frequency heating frequency in hertz. For operation at the27 MHz water antiresonance frequency, α would be about 5.5 meterswithout any hydrocarbon resource 21′ present. The loading effectvariable, k, in practice may vary from about 0.4 to 0.9 depending on thedielectric constant and electrical conductivity of the hydrocarbonresource 21″.

The RF source 22″ may include an RF amplifier, for example, or an activedevice that amplifies a weak electrical current into a stronger one soan electrical gain is provided. The RF source 22″ may include one ormore active devices, such as, for example, semiconductor devices orvacuum tubes. An example RF source 22″ may be a grounded grid amplifierusing a tetrode vacuum tube, for example, the 4CW100000E, manufacturedby CPI Eimac and Associates of Palo Alto, Calif. Of course the RF source22″ may also include a power source, such as a DC power source, and/orother components, as will be appreciated by those skilled in the art.

The apparatus 20″ is advantageously self exciting, i.e. a radiofrequency oscillator is provided in situ by feedback from the RFapplicator 23″. In a self excitation mode, the RF applicator 23″ doesdouble duty as an oscillator tank circuit and a radio frequency heatingfield applicator. The feedback signal used to drive the RF source 22″ oramplifier into oscillation is obtained from a coupling loop 56″ or othercoupling structure located within the enclosure 33″. The feedback signalloops the current through the RF source 22″ to produce oscillations atthe resonant frequency of RF applicator 23″. For example, when the primepower (DC) to the RF source 22″ is first turned on, the output of the RFsource, or amplifier, may include only noise, which travels around thefeedback loop, and is filtered, in frequency, by the RF applicator 23″.The RF power quickly becomes a single frequency. Electrical currentsurges back and forth along the divider 51″ with the AC cycle, so thedivider 51″ functions as a transmission line resonant filter orstripline cavity resonator, for example. The result of the selfexcitation causes a sine wave of electrical current at the outputterminals 57 a″, 57 b″ of the RF source 22″, although other waveformsmay be produced or used. For example, a nonlinear amplifier could beemployed and a serrasoid waveform obtained.

First and second coaxial feedlines 42 a″, 42 b″ couple the RF source 22″to the divider 51″ and the enclosure 33″, respectively. The first andsecond coaxial feed lines 42 a″, 42 b″ convey the amplifier outputsignal and feedback signals to and from the RF applicator 23″. Ofcourse, the RF source 22″ may not be self exciting, so a fixed frequencyoscillator, such as, a quartz crystal oscillator may be used to initiateoscillation. The self excitation/feedback mode advantageously providesfrequency autotracking. In other words, the oscillation frequencyautomatically corresponds to the resonant frequency of the RF applicator23″ for increased efficiency.

The apparatus 20″ further includes an auxiliary RF radiating element62″. The apparatus 20″ also includes an auxiliary RF source 61″ coupledto the auxiliary RF radiating element 62″ and configured to operate at afrequency different than a frequency of the RF source 22″. More than oneauxiliary power source and auxiliary RF radiating element may be used.

The auxiliary RF power source 61″ may be tuned to the 18 cm wavelengthsof the hydroxyl transition (which are near 1612, 1665, 1667, and 1720MHz). The auxiliary RF radiating element 62″ may be a bowtie dipoleantenna, for example, to expose the hydrocarbon resource toelectromagnetic fields at the 18 cm wavelengths of the hydroxyltransition. The auxiliary RF radiating element 62″ may be another typeof antenna or radiating element.

Hydroxyl radical activity may be enhanced by the 18 cm electromagneticradiation due to initiation reactions, where a single molecule breaksapart into two free radicals, and by other reactions, such as, hydrogenabstraction and radical decomposition, which are also radical based. Theauxiliary 18 cm electromagnetic radiation may be applied in addition tothe electromagnetic fields from the divider 51″.

The radio frequencies used may include the hydroxyl resonancefrequencies, which may correspond to the 18 cm wavelengths of thehydroxyl transition which are near 1612, 1665, 1667, and 1720 MHz. Theradio frequencies may correspond to the liquid water anti-resonance near30 MHz, and, more particularly, 27.12 MHZ, which provide increasedpenetration in the hydrocarbon ore and adjust the dielectric susceptanceof the water relative to the hydrocarbon molecules in water-hydrocarbonmixtures.

The RF applicator 23″ further includes a tuning member 37″ coupledbetween the enclosure 33″ and the divider 51″. The tuning member 37″ isillustratively a capacitor that is electrically coupled to the divider51″ for tuning and electrical loading.

The apparatus 20″ also includes a hydrocarbon separator 46″ downstreamfrom the RF applicator 23″ and configured to generate hydrocarbonfractions, and a hydrocarbon processor 47″ downstream from thehydrocarbon separator and configured to generate at least one liquidfuel from the hydrocarbon fractions. As will be appreciated by thoseskilled in the art, the apparatus 20″ may also include anelectromagnetic shield to reduce unwanted radiation for reducinginterference to communications, and for reducing electromagneticradiation exposure, for example.

Operation of the apparatus 20″ will now be described. The apparatus 20″,and more particularly, the RF applicator 23″, functions as a transverseelectromagnetic (TEM) transmission line internally. In a preferredembodiment, the length α is approximately half the free space wavelengthat the frequency of operation, so α≈c/2f, where c is the speed of lightin meters/second, f is the frequency of the oscillations at the RFsource 22″ in Hertz, and α is in meters. Of course the hydrocarbonresource may affect the length-to-frequency relationship of the RFsource 22″. This may result in a relatively small reduction offrequency, for example. With self excited oscillations, the length andfrequency are automatically adjusted so as more of a hydrocarbonresource is introduced, the frequency typically drifts downwards tofollow the RF applicator 23″ resonance.

Dimension β corresponds to the location where the first coaxial feedline 42 a″ coupled to the divider 51″ from the RF source 22″ output.Dimension β sets the load resistance seen by the RF source 22″, forexample. When dimension β is small and the coupling location of thefirst coaxial feed line 42 a″ is located relatively close to thegrounded end 52″, the load resistance referred by the RF applicator 23″will typically be relatively small in value. When the coupling locationof the first coaxial feed line 42 a″ is moved away from the grounded end52″, the load resistance referred by the RF applicator 23″ is increased.50 ohms of resistance may be obtained when the β≈0.05α. The resistanceresponse characteristic is that of the tangent function, e.g. r isproportional to tan(πβ/α).

The electromagnetic fields provided by the embodiments will now bedescribed (FIG. 8). The RF electrical currents 86″ on the divider 51″are oriented in the z-axis out of the page at the instant in timeexamined, and the electrical currents 84″ on the inside of theelectrically conductive enclosure 33″ are oriented in the z-axis intothe page, so the X symbol indicates a flux vector into the page and adot symbol indicates a flux vector out of the page. Electric near fields81″ (E fields) are produced by the flow of electrical currents 84″, 86″as they separate charge inside the RF applicator 23″. Magnetic nearfields 82″ (H fields) are produced by the conveyance of charge on thedivider 51″ and elsewhere.

As will be appreciated by those skilled in the art, the RF applicator23″ produces straight flux line orthogonal E and H fields of uniformamplitude over most of the interior of the enclosure 33″. Thisadvantageously provides uniform application of the electric and magneticfields to the hydrocarbon material 21″. Indeed the orthogonalcharacteristics of a planar electromagnetic wave are synthesized in anenclosure that may be electrically small and evanescent, which isanother advantage.

A method aspect will now be described. The method is for the adjustmentof field impedance in Ohms so that stronger or weaker electric andmagnetic fields can be adjusted. γ is the distance from end of the RFapplicator 23″ and the conduit 41″, or the hydrocarbon resource 21″(FIG. 7). The dimension γ may be particularly important as it adjuststhe field impedance Z applied to the hydrocarbon resource 21″. The fieldimpedance is the ratio of the amplitudes of the E and H field componentsthat are applied to the hydrocarbon resource, i.e. ore, so that Z=E/Hwhere Z is the electromagnetic field impedance, E is the intensity ofthe electric field in volts/meter, and H is the intensity of themagnetic field in amperes/meter. When γ is relatively small in value,and the conduit 41″ is near the grounded end 53″, the electric fieldimpedance may be relatively low, and relatively strong magnetic fieldsare applied to the hydrocarbon resource 21″. When γ=α/2 the conduit 41″is in the center in the RF applicator 23″, or enclosure 33″, the fieldimpedance is high and relatively strong electric fields and weakmagnetic fields are applied to the hydrocarbon resource 21″.

This may be particularly advantageous over the prior art whoseelectromagnetic field impedance was unadjustable and generally 377 Ohmsdue to the formation of waves. In the RF applicator 23″,quasistationary, reactive, near fields are applied in preference to farfield waves.

As described in co-pending patent application Ser. No. 13/079,279, filedApr. 4, 2011, which is assigned to the present assignee, and wherein theentire contents of which are herein incorporated by reference, magneticfields having an amplitude of 7 amps per meter were applied to richAthabasca oil sand for 18 minutes, and the aromatic content of the orewas reduced from 32.2% to 0.96%. The apparatus 20″ provides a surfaceplant for the purposes of the aromatic to polar molecule conversion inrich Athabasca oil sand.

Electric near fields of 1600 volts per meter have been tested onpipeline grade bitumen (i.e., dilbit) with significant molecularcracking at a temperature below the boiling temperature of water at sealevel. The application of radio frequency electromagnetic fields mayprovide a bulk low temperature steam cracker for hydrocarbons becausethe kinetic energy of the water molecules in-situ in thewater-hydrocarbon mix are greatly raised by the electromagnetic fields.The kinetic energy of molecules is of course the temperature of thematerial. Thus, the radio frequency relative to the water antiresonancefrequency may be adjusted to near 30 MHz, and more particularly, 27.12MHz, to adjust the reactivity of the water or hydroxyl radical in thehydrocarbons. As will be appreciated by those skilled in the art, radiofrequency electromagnetic fields typically provide a catalyst effect toincrease the speed of chemical reactions, and the radio frequencyelectromagnetic fields may selectively increase the activity of onemolecular species over another in the reaction according to moleculardielectric constant, molecular magnetic moment, selected radiofrequency, applied field type electric or magnetic.

Another method aspect is directed to a method for processing ahydrocarbon resource 21″. The method includes applying radio frequency(RF) power from an RF source 22″ to an RF applicator 23″ coupled to theRF source. The RF applicator 23″ includes an enclosure 33″ beingelectrically conductive and having a passageway 41″ therethrough toaccommodate a flow of the hydrocarbon resource, and a divider 51″ beingelectrically conductive and positioned within the enclosure. The methodfurther includes flowing the hydrocarbon resource 21″ through thepassageway 41″ to process the hydrocarbon resource with the RF power.

The embodiments described herein are particularly advantageous for oredehydration (water removal) at frequencies away from the 27 MHz waterantiresonance frequency. Further details of RF heating may be found inapplication Ser. No. 12/835,331, filed Jul. 13, 2010, which is alsoassigned to the assignee of the present application, and the entirecontents of which are herein incorporated by reference.

As will be appreciated by those skilled in the art, cogenerationtechniques may be used in conjunction with the embodiments describedherein to further increase process efficiency. For example, waste heatfrom electrical power generation may be used to conductively preheat thehydrocarbon resource 21″ prior to or during treatment with RFelectromagnetic energy.

Many modifications and other embodiments of the invention will come tothe mind of one skilled in the art having the benefit of the teachingspresented in the foregoing descriptions and the associated drawings.Therefore, it is understood that the invention is not to be limited tothe specific embodiments disclosed, and that modifications andembodiments are intended to be included within the scope of the appendedclaims.

That which is claimed is:
 1. An apparatus for processing a hydrocarbonresource comprising: a radio frequency (RF) source; and an RF applicatorcoupled to said RF source and comprising an electrically conductiveenclosure having a passageway therethrough to accommodate a flow of thehydrocarbon resource, and an electrically conductive divider positionedwithin said electrically conductive enclosure; an auxiliary RF radiatingelement within said electrically conductive enclosure; and an auxiliaryRF source coupled to said auxiliary RF radiating element and configuredto operate at a frequency different than a frequency of said RF source.2. The apparatus according to claim 1 wherein said RF source and said RFapplicator are configured to perform at least one of heating,dehydrating, cracking and hydrogenation of the hydrocarbon resource. 3.The apparatus according to claim 1 wherein said electrically conductivedivider has an elongate shape with opposing ends coupled to adjacentportions of said electrically conductive enclosure and with opposingsides spaced inwardly from adjacent portions of said electricallyconductive enclosure.
 4. The apparatus according to claim 3 wherein saidelectrically conductive divider has a convex shape.
 5. The apparatusaccording to claim 1 wherein said RF applicator further comprises atleast one tuning member coupled between said electrically conductiveenclosure and said electrically conductive divider.
 6. The apparatusaccording to claim 1 wherein said RF source is configured to supply RFpower at 27 MHz.
 7. The apparatus according to claim 1 wherein thehydrocarbon resource comprises at least one of oil sand, bitumen,pipeline diluted bitumen, crude oil, and synthetic crude oil.
 8. Anapparatus for processing a hydrocarbon resource comprising: a radiofrequency (RF) source; and an RF applicator coupled to said RF sourceand comprising an electrically conductive enclosure having a passagewaytherethrough to accommodate a flow of the hydrocarbon resource, anelectrically conductive divider positioned within and extending along alength of said electrically conductive enclosure, and having an elongateshape with opposing ends coupled lengthwise to adjacent portions of saidelectrically conductive enclosure and with opposing sides spacedinwardly from adjacent portions of said electrically conductiveenclosure so that the hydrocarbon resource flows around at least one ofa top and bottom thereof, and the opposing sides thereof, and at leastone tuning member coupled between said electrically conductive enclosureand said electrically conductive divider.
 9. The apparatus according toclaim 8 wherein said RF source and said RF applicator are configured toperform at least one of heating, dehydrating, cracking and hydrogenationof the hydrocarbon resource.
 10. The apparatus according to claim 8wherein said electrically conductive divider has a convex shape.
 11. Theapparatus according to claim 8 further comprising: an auxiliary RFradiating element within said electrically conductive enclosure; and anauxiliary RF source coupled to said auxiliary RF radiating element andconfigured to operate at a frequency different than a frequency of saidRF source.
 12. An apparatus for processing a hydrocarbon resourcecomprising: a radio frequency (RF) source; an RF applicator coupled tosaid RF source and comprising an electrically conductive enclosurehaving a passageway therethrough to accommodate a flow of thehydrocarbon resource, and an electrically conductive divider positionedwithin said electrically conductive enclosure; and a hydrocarbonseparator downstream from said RF applicator and being configured togenerate hydrocarbon fractions.
 13. The apparatus according to claim 12wherein said RF source and said RF applicator are configured to performat least one of heating, dehydrating, cracking and hydrogenation of thehydrocarbon resource.
 14. The apparatus according to claim 12 whereinsaid electrically conductive divider has an elongate shape with opposingends coupled to adjacent portions of said electrically conductiveenclosure and with opposing sides spaced inwardly from adjacent portionsof said electrically conductive enclosure.
 15. The apparatus accordingto claim 14 wherein said electrically conductive divider has a convexshape.
 16. The apparatus according to claim 12 wherein said RFapplicator further comprises at least one tuning member coupled betweensaid electrically conductive enclosure and said electrically conductivedivider.
 17. The apparatus according to claim 12 wherein said RF sourceis configured to supply RF power at 27 MHz.
 18. The apparatus accordingto claim 12 further comprising a hydrocarbon processor downstream fromsaid hydrocarbon separator and being configured to generate at least oneliquid fuel from the hydrocarbon fractions.
 19. The apparatus accordingto claim 12 wherein the hydrocarbon resource comprises at least one ofoil sand, bitumen, pipeline diluted bitumen, crude oil, and syntheticcrude oil.